<!DOCTYPE html>
<meta charset="UTF-8">
<title>CSS Reference: symbols function, invalid</title>
<link rel="author" title="Xidorn Quan" href="https://www.upsuper.org/">
<style type="text/css">
  @counter-style triangle-right {
    system: cyclic;
    symbols: \25b8;
    suffix: ' ';
  }
  @counter-style triangle-left {
    system: cyclic;
    symbols: \25c2;
    suffix: ' ';
  }
  @counter-style triangle-down {
    system: cyclic;
    symbols: \25be;
    suffix: ' ';
  }
  @counter-style triangle-up {
    system: cyclic;
    symbols: \25b4;
    suffix: ' ';
  }

  ul {
    padding: 0;
    list-style-position: inside;
  }

  .t-u { list-style-type: triangle-up; }
  .t-d { list-style-type: triangle-down; }
  .t-r { list-style-type: triangle-right; }
  .t-l { list-style-type: triangle-left; }
  div { font: 16px system-ui; margin: 1em; border: 1px solid gray; }
  li::marker { font-family: inherit; }
</style>

<div style="width: 10em;">
<ul dir="ltr">
  <li class="t-r">closed ltr
  <li class="t-d">open ltr
</ul>
<ul dir="rtl">
  <li class="t-l">closed rtl
  <li class="t-d">open rtl
</ul>
<p dir="ltr">&#x25b8;&nbsp;closed ltr
<p dir="rtl">&#x25c2;&nbsp;closed rtl
</div>
<div style="writing-mode: vertical-lr; height: 10em;">
<ul dir="ltr">
  <li class="t-d">closed ltr
  <li class="t-r">open ltr
</ul>
<ul dir="rtl">
  <li class="t-u">closed rtl
  <li class="t-r">open rtl
</ul>
<p dir="ltr">&#x25be;&nbsp;closed ltr
<p dir="rtl">&#x25b4;&nbsp;closed rtl
</div>
<div style="writing-mode: vertical-rl; height: 10em;">
<ul dir="ltr">
  <li class="t-d">closed ltr
  <li class="t-l">open ltr
</ul>
<ul dir="rtl">
  <li class="t-u">closed rtl
  <li class="t-l">open rtl
</ul>
<p dir="ltr">&#x25be;&nbsp;closed ltr
<p dir="rtl">&#x25b4;&nbsp;closed rtl
</div>
